Assisted colonisation as a climate change adaptation tool Biodiversity Node of the NSW Adaptation Research Hub
Masterclass content Assisted colonisation as a climate change adaptation tool Rachael Gallagher Are we ready to move species threatened by climate change? A survey of practitioners and researchers Nola Hancock Ethical considerations when pursuing assisted colonisation Bob Makinson Implementing translocations in practice Rachael Gallagher Question and answer between panel and audience
Resources available Content presented today is available in: Two reports with four appendices PART A: Assisted colonisation as a climate change adaptation tool PART B: Monitoring and prioritisation of flora translocations: a survey of opinions from practitioners and researchers Two journal articles Gallagher RV, Makinson RO, Hogbin PT & Hancock N (2014) Assisted colonisation as a climate change adaptation tool Austral Ecology Hancock N & Gallagher RV (2014) How ready are we to move species threatened from climate change? Insights into the assisted colonisation debate from Australia Austral Ecology
What is assisted colonisation? Assisted colonisation is a type of conservation translocation where organisms are intentionally moved outside their indigenous range to avoid extinction of populations of the focal species (IUCN/SSC, 2013) Also called managed relocation, assisted migration, benign introduction
What is assisted colonisation? Examples of AC projects being conducted globally Butterflies in the United Kingdom have been transplanted beyond their natural range limits Melanargia galathea Thymelicus sylvestris Considered among the first successful examples of AC Willis S. G., et al. (2009) Assisted colonization in a changing climate: a test-study using two U.K. butterflies. Conservation Letters 2, 46-52.
When might AC be needed? Scenarios under which individual species, assemblages or entire communities may benefit from AC: Loss of suitable climatic habitat in the current range The emergence of novel or non-analogue climates Exposure to multiple stressors Replacement of the loss of an ecological function/service
What are the risks of AC? Invasion science tells us much about the risks involved in moving species outside their range The need to move species beyond their range needs to be weighed against the potential non-target effects on communities at recipient sites
Community reassembly Species are likely to respond to changing climates at different rates Community composition may change as a result Multi-species translocations may be considered when associations between species need to be preserved
Ecosystems at risk Some ecosystems will be more vulnerable than others
Ecosystems at risk Certain environments may be more vulnerable to climate change and their species in need to AC The alpine zone (though fewer options may exist in a practical sense for moving species) North-eastern NSW (particularly winter temps) South-west NSW (reduction in rainfall predicted) Marine and freshwater habitats
Identifying candidate species Species that cannot adapt in-situ or migrate are candidates for assisted colonisation What is the evolutionary potential of species? - Dependent on generation time of an organism (i.e. time taken to reach reproductive maturity) Organisms can respond without evolution via modifying their physiology during their lifetime
Identifying candidate species Species that cannot adapt in-situ or migrate are candidates for assisted colonisation How likely is it that species will be able to migrate? - Dispersal capacity varies between species e.g. some plant seeds are adapted for long-distance dispersal by wind, water or in the gut of animals. However, long-distance dispersal events are rare and not all seeds have adaptations for dispersal
Identifying candidate species Species that cannot adapt in-situ or migrate are candidates for assisted colonisation How likely is it that species will be able to migrate? - matrix of different land-uses and habitats makes migration difficult for some species e.g. dragonflies depend on waterbodies and are poor migrators Changes in land-use may fragment habitat for plants, particularly soil specialists
Identifying candidate species Species exposed to multiple threats are at risk Situations likely to exacerbate the impact of climate change include: Habitat fragmentation Vegetation clearing Invasion by weeds, pests and pathogens Changes to disturbance regimes
Identifying candidate species The traits of species can help to inform prioritisation Species with the following may have an increased need for proactive adaptation measures: Long generation times Narrow distributions (climate or soil breadths) Specialist mutualisms Physiological constraints
Identifying candidate species Genetic and demographic considerations Small effective population size is associated with: Reduced genetic diversity Higher rates of inbreeding depression Increased vulnerability to demographic and environmental stochasticity All these factors increase extinction risk
Identifying candidate species A decision tool for prioritising species for translocation was developed in conjunction with the Australian Network for Plant Conservation A set of seven, dichotomous questions on: - Species survival - Taxonomic certainty - Recipient site selection - Long-term funding
Existing approaches to AC Other frameworks exist for assessing candidate species for assisted colonisation
Existing approaches to AC Quantitative methods exist for assessing the vulnerability of individual species These are typically based on: Predictive models Phylogenetic analyses Palaeoecological records Functional traits Current Future
Experimental AC How can we increase our knowledge about the practice of assisted colonisation? Experimental translocations have been undertaken Refinement of techniques for moving species Monitor current translocations
Resources available Appendix 1: Compilation of established flora translocations in Australia
Resources available Appendix 2: Global case studies of experimental assisted colonisations
Resources available Appendix 3 & 4: List of published reviews on flora/fauna translocations